Figure 1.
Under this schema, developers advancing a project choose locations for their project that avoid environmental impacts. If impacts cannot be completely avoided, they then take steps to minimize impacts. Once impacts are minimized to the extent possible, restoration opportunities are pursued. Residual impacts not addressed by the previous steps are then offset through compensatory mitigation, using ratios that result in a net positive impact on biodiversity. Adapted from Convention on Biological Diversity 2008 [54].
Figure 2.
Conservation value in the Mojave Desert Ecoregion.
The conservation values categories are depicted on the map as follows: dark green areas are Ecologically Core, light green are Ecologically Intact, orange are Moderately Degraded, and red are Highly Converted (adapted from Randall et al. 2010). Subregions of the Mojave Desert are shown in the purple-white outline; labels indicate the 1. Northern, 2. Western, 3. South-central, 4. Central, 5. Southeastern, and 6. Eastern subregions. Urbanized land is grey and highways are in grey lines. The location of the ecoregion in the coterminous United States is shown in the inset map.
Figure 3.
Conservation values in potentially suitable lands for solar development below 5% slope angle.
Urban areas, water bodies, and lands outside of private or BLM multiple use ownerships, and areas above 5% slope were removed. Conservation value colors are the same as Figure 2. Lands in orange and red are classified as lower conservation value lands for which energy production estimates are provided in the results.
Table 1.
Area (ha) of land by land ownership, conservation value, and percentage slope angle.
Figure 4.
Land ownership in potentially suitable lands below 5% slope with Moderately Degraded and Highly Converted conservation value.
Blue areas are private lands and dark red areas are BLM land without designation. Areas outlined in orange are designated open off-highway vehicle areas on BLM land in California, accounting for 10% of the 211,000 ha in lower conservation value on BLM land and would not be suitable for development. Conservation values adapted from Randall et al. 2010.
Figure 5.
Parcel size class distribution within private lands of California that are of lower conservation value.
These are only within areas that are potentially suitable for solar development below 5% slope. The presence of high rates of parcelization on private land acts as a disincentive to site large solar projects in more degraded areas.
Figure 6.
Percent of representation goals that would not be attainable if all areas potentially suitable for solar development were to be developed.
The goals refer to a hypothesized amount of each habitat that needs to be managed for conservation to meet long-term viability needs for representative biodiversity of the ecoregion. Goals are based on Randall et al. 2010.
Table 2.
The extent of ecological system targets that occur within BLM Right of Way applications in California or Nevada that also occur within Ecologically Core or Ecologically Intact conservation value categories (from Randall et al. 2010).
Figure 7.
Scenarios of suitable mitigation areas using the future ratios.
This map shows the private land-only (pink) and the mixed ownership (blue) scenarios, with planning units that are shared in both scenarios (teal with outline). The private land-only solution is more dispersed and was not able to offset impacts for five targets in a subregion (grey outlines, labeled in Figure 2), most notably a deficit of over 23,000 hectares of suitable desert tortoise habitat in the Central Mojave subregion, north and east of Barstow, CA. Urbanized areas are shown in light grey. The extent of Ecologically Core (darker green) and Ecologically Intact (light green) is shown for reference (adapted from Randall et al. 2010). Projects used to calculate impacts and drive mitigation demand are shown in brown.
Table 3.
Performance of compensatory mitigation scenarios.
Table 4.
Compensation ratios for current and future mitigation scenarios.